Catalyzer for ethylene polymerization and copolymerization and preparing method thereof

A catalyst for the polymerization or copolymerization of ethene and a preparation method thereof belong to the field of an olefin polymerization catalyst. The catalyst includes a main catalyst component and at least one organic aluminum compound; the main catalyst component includes a magnesium compound, at least one titanium compound and at least one organic alcohol compound. The magnesium compound is an output obtained by dissolving magnesium halide in a mixed solvent which contains an organic epoxide and an organic phosphor compound. During the preparation process of the catalyst, an alkane compound is used as an agent for assisting precipitation. The catalyst is provided with high catalytic activity and better hydrogen response. Simultaneously, the invention also relates to a preparation technique for the catalyst for the polymerization or copolymerization of the ethene. The catalyst is applied to the techniques of slurry polymerization and gas phase fluidized bed or combination; the grain diameters of the obtained polymer are uniform; in addition, the grain diameters are narrowly arranged.